New BMP Combo Drive and Jackshaft Kit

Now this is what I've been waiting for! We need some estimated max speed for the the most popular engine configurations with the stock wheel sprocket. Wondering if I can use my 28T wheel sprocket with this setup, may need to install some kind of tensioner pulley to keep everything in proper alignment. Perhaps the belt/chain setup is the safest way to go in case of chain misalignment?
 
Last edited:
Wondering if I can use my 28T wheel sprocket with this setup.

You will not be able to use that 28t sprocket. The resulting gear ratio would be too high.

Max jackshaft ratio = 3.75:1.....
28t wheel/8t jackshaft = 3.5:1.....
3.75 x 3.5 = 13.125:1.....too high.
 
Now this is what I've been waiting for! We need some estimated max speed for the the most popular engine configurations with the stock wheel sprocket. Wondering if I can use my 28T wheel sprocket with this setup, may need to install some kind of tensioner pulley to keep everything in proper alignment. Perhaps the belt/chain setup is the safest way to go in case of chain misalignment?

Check the website, it has a table with estimated speeds with different size wheel sprockets. Most stock sprockets that come with the Import kits are 44tooth. With the belt jackshaft this would give you a 15.7:1 gear ratio, and with the chain jackshaft this would give you an 18.6:1 ratio. No belt tensioner is needed with the current belt/pulley combo, but if you were to go to a different combo you may need a tensioner. I've attached a couple of photos of a belt tensioner that can be added if needed.....the same concept can be applied for a chain tensioner as well.
 

Attachments

  • belt_tensioner.jpg
    belt_tensioner.jpg
    48.9 KB · Views: 775
  • belt_tensioner1.jpg
    belt_tensioner1.jpg
    93.2 KB · Views: 7,056
Very informative data from the BMP website on the jackshaft ratio / max speed. Looks like this is a very well engineered drive system that won't cost you an arm and a leg. My congrats to BMP on a very user friendly drive system and I will definitely be placing an order. Small question slightly off topic. Why doesn't BMP offer a 1-1/2" steel roller for the friction drive kit any more? I thought it was available at one time in the past.
 
Small question slightly off topic. Why doesn't BMP offer a 1-1/2" steel roller for the friction drive kit any more? I thought it was available at one time in the past.

We never had a 1.5" steel roller but we did have a 1.5" urethane roller. It is a stock part you can get from www.mcmaster.com (part #2475K32). We stopped offering it because a few people had it shred up on them. Also, they slip instantly if they get even a drop of water on them, much worse than a steel roller on wet roads. They are offered in different durometers, soft to hard....we used the hard one, but maybe a softer one may have worked better. I didn't have any problems with it myself on dry roads, but I only put about 100 miles on it. It would cost you about $30 plus shipping if you ever wanted to test it out.
 
Thanks BMP. I don't have your kit yet but I have been helping promote it because you made the product I wish I'd bought in the first place, and you make a product in USA.

I am saving small change and gift $ to buy one in the future. I already have the hybrid/comfort bike for it. I'm just waiting!

I really like the new chain-driven wheel setup! I LOVE Lawn and Garden and industrial trimmer engine equipment so this is a strong related interest. I think these 2 kits are set to start a transportation revolution in America, as long as Big Brother doesn't jump on it and tax the # out of it.

Can't wait to buy.
 
I have a technical question. If a bicycle uses a 11-34 tooth cassette on a standard shimano mtn bike wheel, can the chain drive of the BMP kit be made to turn the 34 tooth cog, if 1 or 2 other cogs are deleted by spacers so the pedal chain does not conflict with it? I know it will still have a slight drag from the clutch maybe, but at least it can free coast, and eliminate the LH drive cog system.
 
Thanks BMP. I don't have your kit yet but I have been helping promote it because you made the product I wish I'd bought in the first place, and you make a product in USA.

I am saving small change and gift $ to buy one in the future. I already have the hybrid/comfort bike for it. I'm just waiting!

I really like the new chain-driven wheel setup! I LOVE Lawn and Garden and industrial trimmer engine equipment so this is a strong related interest. I think these 2 kits are set to start a transportation revolution in America, as long as Big Brother doesn't jump on it and tax the # out of it.

Can't wait to buy.

Hey Happy,

With the price wars that you see happening in this Industry it is tempting to have the kit outsorced and made in China....we are proud to say that our kit is still made in the USA. Of course there will always be a few components that are imported (bearings, quick release and maybe some hardware), but the core components are made here in the USA (clutch drum, channel, drive shaft, frame bracket, drive roller).
 
I have a technical question. If a bicycle uses a 11-34 tooth cassette on a standard shimano mtn bike wheel, can the chain drive of the BMP kit be made to turn the 34 tooth cog, if 1 or 2 other cogs are deleted by spacers so the pedal chain does not conflict with it? I know it will still have a slight drag from the clutch maybe, but at least it can free coast, and eliminate the LH drive cog system.

It can be setup to run the large sprocket on your cassette but this would make the pedals turn also, requiring you to pedal along all the time...not something you want. I think that's correct? Actually now I'm confused....anybody else know?
 
Front Freewheel Cranksets, adapters, and various chainwheel sizes, sold here, separately (e-bike store)
http://www.cyclone-usa.com/store.php?crn=203

SICK bike parts also has Front Freewheel cranksets for SQuare Taper Bottom Brackets. (SICK is awesome! ) http://www.sickbikeparts.com/Products/Cranks.html


I'm mostly interested because of these two ideas:

A person in a state with certain clauses in the motor bicycle laws is not required to use pedals, if the bike is under certain CC and is actually a bicycle frame and wheels. I am trying to remember what state now, will look in the forums, or someone can chime in. This would allow a RH drive side and use of common wheel parts, with a freecoasting hub.

A person who wants to pedal full time anyway can use it like this:


Yes, it would be true in this application. If the engine is small like 32cc, and the automatic clutch is still used, it shouldn't be a problem, because pedaling full time would work well on some applications, especially since you say it can be pedaled with the engine off, correct? 2 cycle engines used for this will have a fast throttle response, so letting off the gas lever would disengage the clutch nearly instantly. A dual kill switch setup with thumb buttons for each hand would be effective for a safety measure. Extra care would have to be taken to let off the gas when changing speeds.

Someone on this forum once modified a Shimano hub or a shimano freewheel to use a standard BMX freewheel in place of a lockring or smallest cog. This would eliminate the multi speed ability though, but would allow use of spacers to create a place for the motor chain to fall into if it ever derailed due to the motor quick release bracket loosening.

I would use this on a bike with BMX pegs so I could start the bike, then ride on the pegs like a sport bike. With a short crank like 160-175, you shouldn't have to worry about grounding out the pedals.

The front freewheel cranks sold for shift kits could also be employed. This would leave one with ONE motor speed gear, and various pedal speed gears (minus deleted gear for space to prevent chain rub). This would be IDEAL for me because I live in TX where the multi speed motor/shift kit is not legal, as far as I know. It would also be a perfectly fine setup for anyone. With pedal speeds, you can always crank your feet on the hills to power up, then coast for the downhill and flats.
 
Last edited:
Back
Top